The subject invention relates to emulsion polymerized crosslinked acrylic rubbers and their use as tougheners for polyamide resins.
Additives useful as polyamide tougheners are well known in the art. U.S. Pat. No. 4,174,358 issued on the application of Epstein discloses adding, to the polyamide, 1 to 40 weight percent of at least one polymer having a particle size of 0.01 to 3.0 microns, and a tensile modulus of 1.0 to 20,000 psi, said polymer being either a branched or straight chained polymer, i.e., noncrosslinked.
Further, a number of U.S. Patents assigned to Rohm & Haas, e.g., U.S. Pat. Nos. 3,668,274; 3,793,402; 3,796,771; 3,985,703; 4,086,300; and 4,148,846, as well as J5 4048-850 and J5 4048-851 assigned to Toray Industries, Inc. all disclose the use of acrylic rubber tougheners for polyamide resins wherein the outer layer of the toughener is necessarily rigid, i.e., has a glass transition temperature of greater than 20.degree. C.